2016-12-09T15:20:15ZExperimental methods in building acoustics for evaluating the flanking transmissionhttp://hdl.handle.net/10198/1845
Título: Experimental methods in building acoustics for evaluating the flanking transmission
Autor: Andrade, C.A.R.
Resumo: All the scientific work must have at the beginning presupposes and assumptions clarified, that could lead to an objective more easily to accomplish. In this line of thought, the present work is to achieve and clarify those presupposes and assumptions. The design of building and his constructions techniques must be built in such a way that the noise perceived by the occupants is kept down to a level that will not threaten their health and satisfactory living conditions. The acoustical comfort is nowadays one of the main issues for the satisfaction and integration on the society. This has more relevance in developed countries.
There are many places where the normal human living is developed: home, work, leaser places, etc, has there are many forms of sound power that disturb those places. However, where the sound perturbation must not reach intolerable levels (acoustical comfort) are in buildings, especially in living buildings. Nowadays is known that sound could be transmitted by structural vibration or by other paths than the separating element of the dwellings. These paths could increase the sound levels of the adjoining rooms with a bigger importance than the supposed a few years ago. The present and future works are more a contribution to obtain better acoustical conditions in buildings and put to the scientific community more knowledge and “savoir faire”.
Firstly a search was made in reviews, books and papers specialized in the areas of knowledge of building acoustics and flanking transmission. The information recovered was treated to clarify all the present work done till the moment and to put us in the center of the issue.
Secondly several measurements were performed in an old building of the university (in situ measures), by pressure method and intensity method. Those measures were then treated, processed, compared and finally discussed to accomplish the main objective of this work, which is getting an objective theme to the future doctoral thesis.
Descrição: Trabajo Tutelado2003-01-01T00:00:00ZMoldações cerâmicas compósitashttp://hdl.handle.net/10198/1685
Título: Moldações cerâmicas compósitas
Autor: Rocha, João
Resumo: O fabrico rápido de ferramentas, sem necessidade de maquinagem das faces de trabalho pode ser
feito utilizando moIdações cerâmicas. Este processo utilizado na produção de peças de pequenas
dimensões (de 50x50x25 mm até 250x250x250 mm) é mais económico que os processos
convencionais de arranque de apara. Verifica-se, no entanto, que o fabrico de peças de grandes
dimensões (maiores que 250x250x250 mm) tem um custo elevado.
Neste trabalho, desenvolveu-se uma técnica e uma metodologia, tendo em vista o fabrico de
moldações cerâmicas compósitas de grandes dimensões, superiores a 250x250x250, destinadas à
produção rápida de ferramentas a baixos custos quando comparados com o processo tradicional.
As propriedades destas moldações foram testadas por forma a reflectir as condições mais adequadas
para resistir ao efeito do vazamento do metal liquido. Por forma a validar o processo, procedeu-se ao
vazamento de 2 ferramentas metálicas em liga cobre-berílio. The fast production of tools, without the use of any machining on the work faces can be made through
shaw casting. This process used in the production of parts of small dimensions (from 50x50x25 mm to
250x250x250 mm) is more economic than the conventional machining processes. It is verified,
however, that the production of parts of great dimensions (bigger that 250x250x250 mm) has a high
cost.
In this piece of work, a technique and a methodology were specifically developed for the production of
shaw casting composite of great dimensions, bigger than 250x250x250, destined to the fast
production of tools, with a lower cost than the traditional process.
The properties of the casting were tested in order to demonstrate the most adequate conditions to
resist the effect of the pouring of the liquid metal. In order to validate the process, the pouring of 2
metallic tools in copper-beryllium alloy was executed.2000-01-01T00:00:00Z